4732results about How to "Improve dynamic performance" patented technology

An independent wheel torque control algorithm is disclosed for controlling motor torques applied to individual electric motors coupled to vehicle wheels in an electric vehicle. In a first range of vehicle states, vehicle steerability is favored so that the operator of the vehicle suffers little or no longitudinal propulsion loss while steering is enhanced. In a second range of vehicle states, vehicle stability is favored. According to embodiments of the disclosure, a desired yaw moment is computed and then may be reduced in magnitude due to system limitations, electrical or friction limits, which prevents the desired yaw moment from being fully realized.

The invention discloses a micro-grid multi-objective optimized operation control method, which comprises the steps of: constructing a micro-grid operation indicator function aiming at wind-light complementary and cold, heat and electricity combined supply micro-grid; then constructing a complete small signal model of the micro-grid for theoretical analysis to provide theoretical guidance for the multi-objective optimized operation control of the micro-grid; and finally on the basis of a multi-objective intelligent optimization theory, comprehensively using power system computer aided design (PSCAD)/electromagnetic transients including direct current (EMTDC) and MATLAB software to design the micro-grid multi-objective optimized operation control method, so as to enable the micro-grid to realize comprehensive optimization of multiple operation indicators such as economy, cleanness, reliability, stability, dynamic performance and the like in different operation modes such as a synchronized operation mode, a mode capable of being switched between the synchronized operation mode and an independent operation mode, an independent operation mode with sudden load change and a resynchronized operation mode.

The invention discloses a charging-discharging system for a V2G bilateral power conversion electric automobile and a control method thereof, which belong to the technical field of intelligent power grids. In the charging-discharging system, a single-phase or three-phase voltage PWM (Pulse Width Modulation) converter (VSC) is taken as a first-grade power conversion circuit, so that energy conversion between an alternating-current power grid and a first direct-current bus is realized; and a symmetric half-bridge LLC (Logical Link Control) resonant bilateral direct current-direct current (DC/DC) converter is taken as a second-grade power conversion circuit, so that energy conversion between a direct-current bus and a power battery pack is realized. The charging-discharging system has the beneficial effects that: the current of the converter power grid side of the first-grade power conversion circuit is approximate to sine wave, so that the harmonic content is small; and the converting efficiency, dynamic performance and power density of the second-grade power conversion circuit are increased, the volume and weight of a charging-discharging device of the electric automobile are reduced, and the safety, reliability and economic efficiency of the system are improved effectively.

The invention relates to a method for controlling dynamic direct voltage of a parallel connection type active electric filter, comprising the following steps: 1. charging current from the power grid pre-charges a capacitor at the direct current side; 2. a lower bridge arm switch of an uncontrolled rectifier bridge is switched on due to control of switching pulse signals transmitted by a controller, the duty cycle of the switching pulse signals increases to a fixed value from zero in a linear manner; 3. the switch of an upper bridge arm and the switch of a lower bridge arm are both simultaneously cut off; 4. a PI controller in an electric ring is placed under a d-q synchronization coordinate system and PI controller initial output value is set; 5. Gn(s) calculation is carried out on sampling value of the power grid voltage and then the sampling value is added to output value of the PI controller in a PI control inner ring in the electric current ring; 6. a repetitive controller is arranged in a repetitive control outer ring of the electric current ring. The invention ensures high stability of DC bus capacitor voltage in dynamic processes such as start, synchronization and load switching of a high-capacity active filter.

The invention relates to a control method and a controller for a DC-DC converter, such as a synchronous Buck converter, which exploits the principle of capacitor charge balance to allow the converter to recover from a positive and/or negative load current step in the shortest achievable time, with the lowest possible voltage undershoot/overshoot. The control method may be implemented by either an analog or a digital circuit. The controller may be integrated with existing controller schemes (such as voltage-mode controllers) to provide superior dynamic performance during large-signal transient conditions while providing stable operation during steady state conditions. The invention also relates to a method and a modification of a DC-DC converter topology that comprises connecting a controlled current source between an input terminal and an output terminal of the DC-DC converter; detecting a load current step to a new load current; modifying a duty cycle of the DC-DC converter; and modifying current through a parallel output capacitor of the DC-DC converter by controlling current of the current source. The methods and circuits provided herein are applicable to Buck converters and Buck-derived converters such as forward, push-pull, half-bridge, and full-bridge converters.

The invention provides a double-motor skidproof differential drive axle used in electric automobiles, which comprises two driving motors, a speed reducer and an output axle which is connected with theThe invention provides a double-motor skidproof differential drive axle used in electric automobiles, which comprises two driving motors, a speed reducer and an output axle which is connected with the speed reducer. The two driving motors are arranged face to face in the middle of the driving axle and connected into a whole through the shell of the speed reducer. The power output by the two drivinspeed reducer. The two driving motors are arranged face to face in the middle of the driving axle and connected into a whole through the shell of the speed reducer. The power output by the two driving motors converges together and flows into the speed reducer; and then the power further drives the left and the right wheels of the electric automobile to rotate through the output axle which is conng motors converges together and flows into the speed reducer; and then the power further drives the left and the right wheels of the electric automobile to rotate through the output axle which is connected with the speed reducer. The driving motors and the speed reducer can be arranged in an engine chamber to achieve compact structure and save space. Simultaneously, in order to solve the problem oected with the speed reducer. The driving motors and the speed reducer can be arranged in an engine chamber to achieve compact structure and save space. Simultaneously, in order to solve the problem of skidding, a skidproof differential device is also arranged in the speed reducer.f skidding, a skidproof differential device is also arranged in the speed reducer.

A functional styrene-butadiene copolymer is disclosed. More specifically, the copolymer is prepared by radical polymerization of a styrene monomer, a butadiene monomer and an epoxy acrylate monomer in an emulsion state and ring-opening of the resultant styrene-butadiene-epoxy acrylate copolymer. When blended with silica, the disclosed copolymer provides excellent wet stopping performance and superior wear resistance. Therefore, it can be usefully applied for industrial materials including fuel-efficient tires, snow tires, belts, hoses, etc.

The invention relates to an intelligent electric vehicle path tracking model prediction control method, belonging to the technical field of control. The aim of the invention is to adopt the intelligent electric vehicle path tracking model prediction control method, wherein the model prediction control method can take account of the safety constraints of a whole vehicle simultaneously and realizeseclectic optimization among vehicle path tracking performance, safety and whole vehicle performance effectively. The method gives thought to intelligent electric vehicle path tracking model building in limited conditions and yaw stabilization controller design based on model prediction control as well as the tracking performance of the vehicle, the safety of the vehicle, the whole vehicle performance, driving comfort and saving and control of energy in the process of carrying out control strategy deduction, and improves the dynamic performance of the whole vehicle. The method gives thought tothe tracking performance of the vehicle (path following and speed following), the safety of the vehicle (preventing slipping, locking, sideward inclining or drifting), the whole vehicle performance (accelerating and braking performance), driving comfort (the change of torque cannot be too great) and saving and control of energy (saving energy on the premise of meeting the performance). The dynamicperformance of the whole vehicle is improved.

The invention discloses an automatic guild system and a multiple task control method and belongs to the transport vehicles field. The automatic guild vehicle system comprises a vehicle part and a guild part; wherein, the vehicle part comprises a vehicle body, an electronic control tank, a central control device, a battery group, a driving mechanism, a suspending mechanism, a road magnetic strip signal sensor, a road RFID radio frequency identification card reader, an anti-knocking mechanism and the like. The guild part comprises a magnetic strip paved on the road and an RFID radio frequency identification card; the vehicle body is provided with a road magnetic strip signal sensor and a road RFID radio frequency identification card reader; the road magnetic strip signal sensor is directly connected with an AD module of the central controller for processing the analog signal transmitted by the road magnetic strip signal sensor. In the invention, the magnetic strip paved on the road and the RIFD radio frequency identification card are used for guiding so as to change lines flexibly and be applicable to flexible manufacturing system.

The active/passive absorber for extended vibration and sound radiation control includes principally two layers. The first layer has a low stiffness per unit area which allows motion in the direction perpendicular to its main plane. The second layer is principally a mass layer. These two combined layers have a frequency of resonance close to one of the main structure. The dynamic behavior of the coupled system makes the active/passive absorber a passive absorbe; however, the first layer can be electrically actuated to induce motion in the direction perpendicular to its main plane. This addition property induces and/or changes the motion of the mass layer and therefore improves the dynamic properties of the active/passive absorber system.

The invention belongs to the power transmission and distribution field, and specifically relates to a pulse width control method of a modular multilevel converter. The method is characterized by determining the switched number of submodules at any time by carrier phase-shifting and then determining switching of the specific submodules by capacitance-voltage balance control, and comprising the steps of carrier comparison, signal acquisition, signal processing, PWM pulse signal generation and the like. The pulse width control method is simple, scientific and reasonable and easy for engineering realization, and has good dynamic property, thus being applicable to occasions with wider range of frequency variation in an AC system and free from restriction of the level number.

A two-freedom robot mechanism with 2D translation and planar parallel connection is composed of a static plat form, a dynamic platform, and 4 branches including 2 active branches and 2 passive branches for linking dynamic platform with static platform. Said active branch consists of a drive arm and a driven arm.

The invention discloses a parallel active filter based on a modularization multi-level converter and a control method of the parallel active filter and belongs to the technical field of power harmonic suppression in a medium-high voltage high-power occasion. The problem that an existing parallel active filter cannot carry out harmonic combination compensation effectively, so that power distribution network electric energy quality is poor is solved. The filter comprises the modularization multi-level converter, a current transformation unit, a harmonic current detecting unit, a current controller, a capacitor C and a power grid electric reactor LS. The modularization multi-level converter is of a half-bridge-type topological structure, and an upper bridge arm and a lower bridge arm of the modularization multi-level converter respectively comprise n submodules SMn. According to the control method, a carrier phase-shifting modulation method is used, so that under the same switch frequency, equivalent switch frequency is high, switching loss is reduced, meanwhile, a capacitive coupling voltage sharing and ring current suppression strategy is used, and capacitor voltages and direct current bus voltages of the submodules are kept stable. The parallel active filter is used for harmonic suppression of a power grid.

This invention relates to: a molding material comprising a bundle of continuous reinforcing fibers (A), a polyarylene sulfide prepolymer (B) comprising at least 50% by weight of cyclic polyarylene sulfide and having the weight average molecular weight of less than 10,000 or polyarylene sulfide (B′) having the weight average molecular weight of 10,000 or greater and the degree of dispersion of 2.5 or lower, and thermoplastic resin (C); a prepreg comprising a resin composition comprising the polyarylene sulfide prepolymer (B) impregnated into a reinforcing fiber; and a method for producing a fiber-reinforced molding substrate comprising step (I) of continuously feeding a bundle of continuous reinforcing fibers, step (II) of combining cyclic polyarylene sulfide with the reinforcing fiber bundle, step (III) of heating the composite obtained in step (II) to subject the cyclic polyarylene sulfide to ring-opening polymerization to convert into polyarylene sulfide, and step (IV) of cooling the composite obtained in step (III) and withdrawing the same.

The invention discloses a bogie for a high-speed rail wagon. The bogie comprises a framework, wherein two transverse ends of the framework are connected with a wheel set through two single-stage suspension systems respectively; a double-stage suspension system and a foundation brake device are arranged on the framework; and the front side and the rear side of the framework are provided with an anti-snakelike damper respectively. By the bogie, two-grade requirements that the shaft weight is 16.5t when the speed of the wagon is 200km/h as well as the shaft weight is 18t when the speed of the wagon is 160km/h can be met simultaneously; and the bogie has the remarkable characteristics of simple structure, high popularity and reliable performance.

The invention discloses a symmetrical half-bridge LLC resonant bidirectional DC-DC converter, which belongs to the technical field of power electronic application. Topological structures on the two sides of the converter are symmetrical, and adopted components adopt a complex function design. When a switching network and a resonant network on one side of a high frequency transformer function, the switching network and the resonant network on the other side are automatically evolved into a rectifier-load network, and the networks on the two sides commonly form the whole LLC resonant converter to realize power conversion in a corresponding direction. Because the structures are completely symmetrical, reverse conversion can be possible; and in the reverse conversion, the topological structures can be automatically reconstructed to form a reverse LLC resonant converter to realize reverse power conversion. The symmetrical half-bridge LLC resonant bidirectional DC-DC converter achieves effective improvements in conversion efficiency, power density, dynamic performance and electromagnetic compatibility, reduces the electrical stress of components at work, has a reduced volume and a reduced weight, and realizes highly-efficient, isolated and bidirectional DC/DC power conversion.

The invention provides a network voltage disturbance generating device, which comprises a three-phase bridge type PWM (Pulse Width Modulation) rectifier and a three-H-bridge three-phase four-wire-system PWM inverter, wherein the alternating current side of the rectifier is connected with an electric network through an L type filter; the direct current side of the rectifier is connected in series with the direct current side of the three-H-bridge three-phase four-wire-system PWM inverter; an LC filter is connected to the alternating current side of the three-H-bridge three-phase four-wire-system PWM inverter; the output end of the LC filter is connected with an isolation transformer; and the secondary side of the isolation transformer is connected with a load. The invention further provides a control method suitable for the device. Due to the adoption of the device provided by the invention, the simulation of a network voltage amplitude, frequency disturbance and an electric network harmonic phenomenon can be realized, bilateral flow of energy can be realized, and active energy transmitted by tested solar-powered grid-connected equipment is fed back to the electric network; and the control method is easy and convenient to implement, and a target reference value can be accurately tracked; and moreover, quick response and small steady-state errors are realized, so that electric network disturbance can be simulated accurately.

The invention discloses a satellite communication Turbo code iterative demodulation method with high dynamic and an extremely low signal-to-noise ratio. The method includes the following steps: (10) converting a received bandpass signal into a baseband signal; (20) acquiring a rough estimation value of frequency offset, and performing carrier frequency offset compensation by using the estimation value; (30) performing matched filtering on the signal subjected to carrier frequency offset compensation; (40) estimating timing frequency offset, and performing timing frequency offset correction onthe filtered signal; (50) preestimating frequency offset, and compensating the signal; (60) performing precision estimation on the frequency offset and phase offset, and compensating the signal subjected to preestimated compensation; (70) performing precision estimation on residual timing frequency offset and timing deviation after carrier offset compensation, and outputting a decoding decision result; and (80) introducing a frequency offset counter to subsequent coded packets, and improving an EM algorithm to complete Doppler frequency offset change tracking. The Turbo code iterative demodulation method disclosed by the invention is low in complexity, high in efficiency and good in adaptability.

The invention relates to the technical field of electric transmission and control, in particular to a speed sensor-less method for estimating the rotor angle and the revolving speed of a permanent-magnet synchronous motor. The method comprises the following steps: a. obtaining the rotor flux linkage amplitude Psi<r> of a permanent-magnet synchronous motor; b. transforming a stator voltage fundamental component to be under an alpha beta coordinate system to obtain u<alpha> and u<beta>; c. transforming the stator current fundamental component to be under the alpha beta coordinate system to obtain i<alpha> and i<beta>; d. carrying out highpass filtering on stator current i<alpha> and i<beta> under the alpha beta coordinate system, and obtaining the differential estimation value sum of the stator current; e. obtaining a stator counter electromotive force estimation value; f. obtaining a rotor revolving speed calculation value omega<rC> and a rotor angle calculation value theta<rC>; g. carrying out lowpass filtering on the rotor revolving speed calculation value omega<rC> to obtain a rotor revolving speed estimation value; h. obtaining the estimation value of a rotor angle starting value; and i. obtaining a rotor angle estimation value. The method has the advantages that only forward calculation, instead of a feedback channel, exists in the method for estimating the rotor angle and revolving speed, and except filter delaying, no dynamic regulation process exists.

A longitudinal, transverse and vertical force integrated control optimization method for electric vehicles driven by hub belongs to that technical field of electric vehicle control. The object of theinvention is to adopt a layered cooperative control structure so as to solve the four shortcomings existing in the prior art control system of a longitudinal, lateral and vertical force integrated control optimization method of an electric vehicle driven by a hub. The invention brings the relationship between vehicle resultant force and four-wheel tire force into the vehicle body six-degree-of-freedom equation to obtain the expected values of vehicle kinematics control target longitudinal speed, lateral speed, vertical speed, pitch angle, roll angle and yaw angle, thereby optimizing the vehicle kinematics control target. The layered longitudinal, lateral and vertical force unified optimal distribution integrated control method eliminates the conflict between different chassis electronic control systems and enhances the complementarity, and comprehensively improves vehicle handling stability and vehicle driving posture, which is embodied in the improvement of vehicle road tracking performance, safety, maneuverability, stability and comfort.

A flexible hose comprising a tube, a knit fabric, and a cover. The knit fabric comprises a hybrid yarn which comprises a first yarn of co-para-aramid fibers and a second yarn of meta-aramid fibers. The hose exhibits significantly improved burst pressure and/or improved impulse fatigue resistance.

The invention discloses a pipelined analog-digital converter (ADC) capable of carrying out background digital calibration. The pipelined (ADC) comprises a sampling hold circuit, M calibrated level circuit modules, N level circuit modules and a back level analog-to-digital conversion module which are sequentially connected in series, wherein each calibrated level circuit module is connected with a corresponding digital calibrated level circuit; the quantized value output port of the level circuit module and the quantized value output port of a back level analog-to-digital conversion module are respectively connected with a time delay and dislocation summation module; and the output end of the time delay and dislocation summation module is sequentially and reversely connected in series in the digital calibrated level circuit. The pipelined analog-to-digital converter provided by the invention has the advantages that the thinking is inventive, the analog circuit has a simple structure, a pseudo random number generator and a multi-way selection switch are additionally arranged on the foundation of the existing technical structure, and the working of other analog circuits can not be unaffected in the working process; and simultaneously, the principle of the digital circuit segment is simple and is easy to realize, the error of the pipelined ADC can be reduced obviously, the linearity of the pipelined ADC can be improved, and the dynamic properties of the pipelined ADC can be improved.